Bolt operating mechanism for machine guns



Jan. 4, 1938. s GREEN 2,104,033

BOLT OPERATING MECHANISM FOR MACHINE GUNS Filed Oct. 11, 1935 24 A; /4Inventur Emmuel, [3. Green J MMW PatentedJan. 4, 1938 PATENT orrica BOLTOPERATING MECHANISM FOR MACHINE G UNS Samuel G. Green, Gray, Ga.

Application October 11, 1935, Serial No. 44,572

4 Claims.

(Granted underv the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757') 5 This invention relates to abolt operating mechanism for machine guns.

. Machine guns are provided with a breech bolt handle to permit manualretraction of the bolt in order to reproduce the action of the gun lmechanism during flringfor the purpose of initially loading the gun andcorrecting stoppages. The reciprocation of the bolt handle during firingof the gun has frequently caused injury to members of the gun crew. 'Inthe heavy 15 machine gun such as the .50 caliber, a considerable eflortis required to initiate retraction of thebolt and in performing thisoperation the gunners hand is frequently injured.

The purpose of this invention is to facilitate 0 manual retraction ofthe breech bolt and to this end the bolt handle is arranged to have aninitial lever action. The handle is also arranged so that it is notretracted by the breech bolt during firing of the gun.

With the foregoing and other object in view, the invention resides inthe novel arrangement and combination of parts and in the details ofconstruction hereinafter described and claimed, it being understood thatchanges in. the precise 30 embodiment of the invention herein disclosedmay be made within the scope of what is claimed without departing fromthe spirit of the invention.

A practical embodiment of the invention is 35 illustrated in theaccompanying drawing, where- Fig.1 is a plan view of a machine gunequipped with the improved bolt operating mechanism.

Fig. 2 is a view in side elevation.

Fig. 3 is a'sectional view on the line 33 of Fig. 2.

Fig. 4 is a plan view of the slide.

Fig. 5 is a view in side elevation thereof.

Referring to the drawing by characters of 45 reference, there is shownthe breech casing 5 of a machine gun having a side plate 6 with alongitudinally extending slot 1 in which the stud 8 of a breech bolt 9reciprocates during actuation of the gun. A frame l0 having a slot I Icorrespond- 50 mg to, but wider than the slot 1, and in alignmenttherewith, is attached to the outside of the side plate by a pluralityof screws or bolts l2.

:The slot H in the frame extends forwardly beyond the front end of theslot I to accommo- 55 date a slide is which is disposed in front of thestud 8 of the breech bolt when the breech bolt is in its extreme forwardor "in battery position. The slide is provided on its upper and lowersides with tongues I l-l4 which ride in grooves l5-I5 formed between therail portions of the frame and the side plate 6. The rear face of theslide is formed with a semi-circular recess It for engaging the stud 8of the breech bolt.

A lever I! having a heel l8 and a toe I9, is pivotally mounted betweenthe heel and toe on a stud bolt 20 which is threaded in the slide. Thelever is laterally confined between a collar 2| and a nut 22 on the bolt20 and a torsion spring 23 embracing the collar has oneendattached tothe collar and the other end to the lever. stop pin 24 is carried by theslide forwardly of the bolt 20 in position to engage the under side ofthe heel I8 01 the lever when the lever is in an upright verticalposition where it has been moved and is held by the spring 23.

A stud bolt 25 is threaded in the frame I 0 and is positioned directlyunderneath the bolt 20 when the slide carrying the bolt 20 is in theforward position. The bolt 25 preferably carries a roller 26 which isadapted to engage the under side of the toe IS.

The upper end of the lever carries a laterally projecting handle 21which is adapted to be grasped by the gunner and acted on to retract theslide.

A plunger 28 is carried by the frame and is normally urged by ajspring29 into the path of movement of the slide. When the slide is in itsforemost position the beveled or pointed end 30 of the plunger engagesin a recess 3| in the slide.

In the normal position of the parts the breech bolt 9 is in battery andthe slide I3 is atthe forward end of the frame where it is releasablyheld against retraction by the plunger 28 and positively held againstforward displacement by virtue of the engagement of the toe IQ of thelever with the roller 26, the lever being limited to an upright verticalposition because of the engagement of its heel l8 with the stop pin 24.The slide and lever remain in this position when the breech boltreciprocates in automatic operation of the gun.

When it is desired to manually retract the breech bolt, the handle 21 isgrasped by the gunner and a rearward pull is exerted. This actionproduces rotation of the lever I1 about its pivot 20 and since the toeof the lever is fulcrumed on the roller 26, the pivot, and the slide l3to which is it secured, are displaced rearwardly. The slide beingconnected to the breech bolt smoothly initiate retraction of the breechbelt which at this time is being unlocked with respect to the barrel. v

When the lever and slide are retracted a distance sufficient for the toel9 to clear the roller, the eflort exerted on the handle causes thelever to be rotated about its pivot until the toe engages the stop pin24 of the slide I3. The lever is now in position parallel to and in linewith the slide I3 so that the pull on the lever is directly transmittedto the slide.

When the slide is fully retracted as shown in dotted lines in Fig. 2 thelever is released. The breech bolt is now free to be returned intobattery by its return spring which was energized upon retraction of thebreech bolt. The stud 8 of thebreech bolt being in rear of the slidecauses the slide to be driven forwardly. As soon as the lever isreleased, the torsion spring 23 restores it to the upright positionwhere the heel l8 engages the stop pin 24. The slide is arrested in itsforward movement when the toe I9 of the lever engages the roller 26.

I claim:

1. In a machine gun, a casing having a side plate provided with a slot;a breech bolt reciprocally mounted in the casing and having a studextending through the slot, 8. frame on the outer side of the sideplate, a slide reciprocallymounted in the frame and engaging the forwardface of the stud on the bolt, a lever having a toe and a heel andpivotally mounted on the slide between the toe and heel, a stop pincarried by the slide in front of the pivot of the lever, a springnormally acting to rotate the lever to a vertical position with itsheelengaging the stop pin, and a member serving both as a fulcrum and a stopcarried by the frame below the pivot of the lever and engageable by thetoe of the lever.

2. In a machine gun, a support, a breech bolt reciprocally mounted inthe support and having a projecting member, a slide reciprocally mountedon the support and engageable with .the' front face of the projectingmember of the breech bolt, a lever having a toe and a heel and pivotallymounted on the slide between the toe and heel, a stop pin carried by theslide in front of front face of the projecting member of the breechbolt, a lever having a toe and a heel and pivotally mounted on the slidein front of the bolt element and between the toe and heeL-a stop pincarried by the slide in front of the pivot of the lever, and a memberservingas a fulcrum and a stop carried bythe support below the pivot ofthe lever. v

4. In a machine gun, a support, a breech boltreciprocally mounted in thesupport and having a projecting member, a slide reciprocally mounted onthe support and engageable with the projecting member of the breechbolt, a lever plvotally

